1. Field of the Invention
The present invention relates to a power supply noise resistance testing circuit, and more particularly, to a power supply noise resistance testing circuit in which a power supply noise necessary to test a power supply noise resistance of a functional block is optimally generated, and a power supply noise resistance testing method for the power supply noise resistance testing circuit.
2. Description of the Related Art
Evolution of an LSI manufacturing process advances increases in speed and degree of integration and a reduction in voltage on an LSI. In recent years, a malfunction of the LSL which is caused by power supply noises has become a large problem.
Up to now, past experiences, a result obtained by evaluating an evaluation sample chip such as a test element group (TEG) chip, a result obtained by simulation, and the like are fed back to the LSI manufacturing process. The LSI is designed in view of a power supply noise resistance (for example, a power supply wiring structure or an on-chip capacitor arrangement) The power supply noise resistance of the LSI changes depending on manufacturing variations or the like.
Therefore, a method capable of easily measuring the power supply noise resistance is required at a time of a shipment inspection of the LSI, an acceptance inspection thereof, or a failure analysis thereof.
In the past, techniques for testing the power supply noise resistance have been developed. An example of the techniques is disclosed in JP 05-107321 A.
JP 05-107321 A discloses an integrated circuit measuring device and the summary of the device is as follows. A noise generated by a power supply noise generating source under the control of a control section of a tester is superimposed on power to be supplied from a power supply to a power supply terminal of an integrated circuit under the control of the control section. Then, the power is supplied to the integrated circuit. A test pattern is inputted into the integrated circuit. A signal outputted from the integrated circuit is compared with an expected value for the test pattern by a comparator. Therefore, a function test is performed in a state in which the noise is superimposed, thereby measuring a noise margin.
A semiconductor device testing device is disclosed in JP 2003-050264 A. The testing device includes a tester for generating a first test pattern signal for function test and a second test pattern signal similar to a simulated power supply noise and an evaluation board in which a noise superimposing circuit is provided and to which a semiconductor device is attached. In the testing device, the first test pattern signal is applied to a signal input terminal of the semiconductor device attached to the evaluation board. The second test pattern signal is applied to the noise superimposing circuit to generate the simulated power supply noise. The power supply noise is applied to a power supply of the attached semiconductor device. Then, the resistance of the semiconductor device to the power supply noise is evaluated.
As described above, in the conventional case, it has been recognized that the easy measurement of the power supply noise resistance is required at the time of the shipment inspection of the LSI, the acceptance inspection thereof, or the failure analysis thereof. However, no power supply noise resistance test is performed on the LSI or only the power supply noise resistance test in which the power supply noise generating source is provided in the tester or on the test board (evaluation board) and the power supply noise is applied from the outside of the LSI is performed as described in JP 05-107321 A or JP 2003-050264 A.
When the integrated circuit is composed of a plurality of functional blocks (hereinafter referred to as IP cores in this section), the power supply noise resistance of each of the IP cores cannot be tested with pinpoint accuracy only by the application of the power supply noise from the outside of the LSI.
Although a low-frequency power supply noise can be applied, a high-frequency power supply noise which is a recent problem cannot be applied.